{"id":"c66060ef-ef35-4ffe-8d2d-c833c1f53957","arxiv_id":"1909.00144","paper_version":1,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":6,"one_line_summary":"The compact radio jet in UGC 05771 probably inflates a kpc-scale 'stalling wind' of shocked gas and may push the galaxy below the normal star formation relation.","lead":"Using Keck, CALIFA and IRAM observations, this paper finds that the young radio jet in the galaxy UGC 05771 is likely driving shocks through its gas out to kiloparsec scales, even though the bright radio emission is only parsecs wide. The galaxy also sits below the normal star formation law, hinting the jet may be suppressing star formation, though the authors cannot prove it.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The kpc-scale radio plasma is inferred from unresolved single-dish flux, not imaged; the 70–80% 'missing' VLBI flux could be on 10–100 pc scales or contaminated, so the central link is not yet secure.","rationale":"The reader's weakest-assumption analysis correctly identifies the unresolved-point: the 70–80 per cent of 1.665 GHz flux not recovered by VLBI is the only evidence directly linking the radio source to kpc-scale jet plasma. My read agrees with this assessment. This concern is load-bearing because the paper's strongest claim is that kpc-scale jet plasma must be responsible for the kpc-scale line emission; without direct imaging, that claim rests on an inference from flux incompleteness and on plausibility arguments from line ratios, kinematics, and the peak-frequency–size correlation. The authors are careful and appropriately hedged elsewhere, and I found no internal inconsistency or circular reasoning. The concern does not overturn the paper; it weakens the certainty of the headline interpretation and justifies the 'CONDITIONAL' verdict rather than a full 'ACCEPT'. If the proposed imaging fails to find diffuse kpc-scale radio emission, the correct conclusion would be closer to 'unverified' for the kpc-scale plasma, although the OSIRIS H2 and [Fe II] results would still support jet-ISM interaction on roughly 200 pc scales. Since the reader already recommended CONDITIONAL, I leave the verdict unchanged.","tokens_in":28405,"tokens_out":4048,"duration_ms":101632,"concrete_test":"Obtain deep low-frequency imaging with the JVLA at 1–2 GHz in B and D configurations, and/or LOFAR at 150 MHz, sensitive to surface brightnesses of roughly 0.1 mJy/beam on angular scales from about 1 arcsec out to several arcmin, and compare the recovered flux with the single-dish spectrum in Fig. 1. If extended radio emission is detected coincident with the CALIFA shocked-gas region and accounts for the missing 70–80 per cent of the 1.4 GHz flux, the inference is supported. If the diffuse flux is absent, confined to <100 pc scales, or dominated by a confusing source, the central claim fails.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The paper's central inference in Section 6.2 is that because VLBI at 1.665 GHz recovers only 20–30 per cent of the single-dish flux, the remaining 70–80 per cent must be kpc-scale low-surface-brightness jet plasma. This step conflates 'not detected by VLBI' with 'emitted on kpc scales.' VLBI is insensitive to any structure smoother than the maximum recoverable angular scale set by the shortest baseline, which at 1.665 GHz is typically tens to a few hundred mas (roughly 10–100 pc at z = 0.025), not necessarily kpc. The comparison also mixes epochs, frequency bands (1.4 GHz catalogues vs 1.665 GHz VLBI) and beam sizes, so the missing flux could include compact emission resolved out by the lack of zero-spacing flux, a faint 100 pc-scale component, or unrelated sources within the arcminute single-dish beams. The kpc-scale shocked gas seen in CALIFA and the offset from the peak-frequency–size correlation are suggestive, but they do not by themselves prove that kpc-scale radio plasma exists; they are consistent with it. Since 'kpc-scale jet plasma must be responsible for this line emission' is the paper's strongest claim, the absence of direct imaging leaves a gap between the data and the conclusion.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper presents a multi-wavelength study of the nearby CSS radio galaxy UGC 05771 with the aim of testing whether jets from a young radio source can drive negative feedback. The authors use Keck/OSIRIS near-IR IFU observations to detect ro-vibrational H2 and [Fe II] emission within ~200 pc of the nucleus, which they attribute to shock-heated gas in a 'stalling wind'. CALIFA optical IFU data reveal elevated velocity dispersions and LINER-like line ratios within ~2 kpc, interpreted as shocked ionized gas. IRAM 30 m CO observations yield a molecular gas mass of ~1.1e9 M_sun and a gas surface density of ~15 M_sun pc^-2. A key argument is that VLBI observations recover only 20-30% of the single-dish radio flux, which the authors interpret as evidence for kpc-scale, low-surface-brightness jet plasma; they conclude that the jets are interacting with the ISM on kpc scales and that the galaxy lies below the Kennicutt-Schmidt relation, suggestive of suppressed star formation. The paper also models the radio spectral turnover with free-free absorption to constrain ISM density and estimates a source age of ~19 Myr.","tokens_in":28680,"tokens_out":10094,"duration_ms":88582,"significance":"If the central inference is correct, the paper provides one of the few detailed case studies showing that compact radio sources can couple to the ISM on scales far exceeding their VLBI size, supporting the 'flood-and-channel' model. The observational work is careful: the authors quantitatively rule out beam smearing as the cause of the broad optical lines and supernovae as the source of the [Fe II] emission, and the use of three independent data sets is a strength. The paper also makes falsifiable predictions: a kpc-scale radio source should be directly detectable with low-frequency or high-sensitivity imaging. However, as discussed below, the key inference from missing VLBI flux to kpc-scale plasma is not unique.","major_comments":[{"comment":"The central claim that 'kpc-scale jet plasma must be responsible for this line emission' (end of Section 6.1) is not uniquely supported by the data. The argument relies on the inference, made in Section 6.2, that the 70–80 per cent of the 1.665 GHz flux not recovered by EVN/VLBA is emitted on kpc scales. VLBI is insensitive to structure on angular scales larger than the maximum recoverable scale set by the shortest baseline, which at 1.665 GHz is typically tens to a few hundred mas (roughly 10–100 pc at z=0.025), not necessarily 1–2 kpc. The missing flux could therefore be emitted on scales of ~10–100 pc, still much smaller than the ~1–2 kpc extent of the shocked gas. The comparison also mixes epochs and frequencies (e.g., 1.4 GHz single-dish vs 1.665 GHz VLBI), and the single-dish beam may include unrelated sources. The authors should quantify the maximum recoverable angular scale for the specific arrays used, and either soften the claim to 'consistent with' or justify why intermediate-scale emission is excluded. The current wording overstates what is a plausible but indirect chain of evidence.","section":"Section 6.1–6.2, Fig. 1"},{"comment":"The free-free absorption model and the resulting source age of ~19 Myr depend on the assumed depth of the absorbing slab, L = 2 kpc, and the bubble radius, R_b = 2 kpc, both taken from the extent of the shocked gas. If the existence of kpc-scale plasma is not independently established (see major comment 1), then this analysis becomes partially circular: the model adopts the very scale under question to derive the ISM density and age. The authors should present these results explicitly as conditional on the extended-jet interpretation, or discuss how the derived parameters would change for a smaller absorbing region (e.g., L ~ 100 pc).","section":"Section 6.4, Table 4 and Eq. (10)"},{"comment":"The kinematic disc model is used both to identify non-circular motions (the counter-rotating core) and as the input for the beam-smearing test that rules out beam smearing. However, the model fit has χ² > 10, indicating a poor description of the data. If the model is inaccurate, the synthetic data cube used for the beam-smearing test may not faithfully reproduce the true line-of-sight velocity distribution, and the conclusion that beam smearing cannot explain the elevated velocity dispersion could be an artifact of the assumed model. The authors should test the robustness of the beam-smearing conclusion against a range of plausible velocity fields (e.g., including a central velocity gradient or a warp).","section":"Section 4.3.4, Fig. 12"}],"minor_comments":[{"comment":"The 'Turbulent Mach number M' is listed with units 'km s−1'; the Mach number is dimensionless. If M = sqrt(3)σ_g/c_s ≈ 34.75, state this explicitly.","section":"Table 4"},{"comment":"The equation for σ_e appears to have a typo: the denominator should be Σ I_i, not Σ σ_{*,i}. As printed, the units do not work.","section":"Section 4.2, Eq. (8)"},{"comment":"The statement that the H2/Brγ ratio 'far exceeds' typical UV-excitation values should be phrased as 'the lower limit on the ratio far exceeds', since Brγ is only an upper limit.","section":"Section 3.4.1"},{"comment":"In the KS-relation discussion (Section 6.3), the statement that UGC 05771 is 'shifted by a factor of 9 ... corresponding to about 1 sigma' does not specify the source of the sigma. Please clarify whether this is the intrinsic scatter in the KS relation or the measurement uncertainty.","section":"Section 4.3.3"},{"comment":"The rms noise values are quoted for a channel width of 5 km s−1 at 112.5 GHz, but the CO(2–1) line is observed near 225 GHz; please give the noise for each line separately.","section":"Section 5.2"},{"comment":"The excitation temperature T≈5000 K is derived from only two detected lines and one upper limit; the authors should emphasize that this is an estimate under the assumption of LTE, which they note cannot be verified.","section":"Section 3.4.1, Fig. 5"}],"recommendation":"major_revision","confidential_remarks":"The paper is a strong observational study, but the principal claim is overstated. The missing-flux argument is suggestive rather than decisive. I recommend that the authors revise the language and add a quantitative discussion of VLBI's sensitivity to extended emission, and perhaps propose a direct observational test. This is within scope for a major revision."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Short version: this is a careful, well-hedged single-object study with genuinely new data, and the main interpretive leap is flagged but not fully closed. It deserves a serious referee, though I would push for a revision that either softens the 'must be responsible for this line emission' wording or gets direct low-surface-brightness radio imaging.\n\nWhat is actually new: the OSIRIS detections of H2 and [Fe II] within 200 pc, the kpc-scale shocked ionised gas in CALIFA, the CO(1-0) and CO(2-1) detections, and the specific comparison to the peak-frequency–size correlation. The data reduction is careful, and the paper does real work ruling out alternatives: beam smearing cannot explain the elevated central velocity dispersion, and supernovae cannot produce the [Fe II] luminosity. The stalling-wind picture is reasonable given the low velocities and ordered rotation. That is a solid observational core.\n\nThe soft spot is the load-bearing inference in Section 6.2: 70–80 per cent of the single-dish flux is not recovered by VLBI, and the paper concludes it must be kpc-scale jet plasma. The stress-test note is right that 'not detected by VLBI' does not mean 'emitted on kpc scales.' VLBI can resolve out any smooth structure larger than the maximum recoverable angular scale, which at 1.665 GHz is typically tens to a few hundred mas—roughly 10–100 pc at this distance, not necessarily kpc. There is also epoch mixing and frequency mixing in the flux comparison, and the single-dish beams are large enough to include unrelated sources. So the conclusion in Section 6.1 that 'kpc-scale jet plasma must be responsible for this line emission' is stronger than the data support. The kpc-scale shocked gas is certainly consistent with extended plasma, and the peak-frequency–size offset is suggestive, but consistency is not proof.\n\nThe Kennicutt-Schmidt offset is handled honestly: the paper says the SFR estimate is an upper limit and that the offset is about 1 sigma. That is fine, though it means the 'negative feedback' part of the title remains an open question rather than a result.\n\nCitation pattern: the method reuse from Zovaro et al. (2019) and the same group's simulations is substantial, but not circular—the new observations stand on their own. The FFA density model adds little new constraint, but it is clearly presented as an application of prior work.\n\nWho is this for? People working on CSS/GPS sources and jet-ISM feedback. As a second object alongside 4C 31.04 it is genuinely useful evidence that compact radio sources can interact with their ISM on scales larger than the VLBI core. My recommendation: send it to peer review. A good referee should ask for the radio completeness argument to be reframed as an upper limit on the size of the missing plasma, and for the 'must' to become 'consistent with' unless direct low-surface-brightness imaging is obtained. That is a revision, not a rejection.","headline":"Careful single-object study with new data whose central claim—kpc-scale jet plasma—is plausible but inferred rather than imaged; deserves peer review with a requested toning-down.","tokens_in":29385,"tokens_out":1819,"would_cite":false,"duration_ms":22542,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"This paper argues that the radio jets of the compact galaxy UGC 05771 extend to kiloparsec scales, shocking and accelerating the surrounding gas, and possibly suppressing star formation.","keywords":["UGC 05771","compact steep spectrum radio source","radio jet","jet-ISM interaction","negative feedback","shocked molecular gas","stalling wind","low-surface-brightness radio plasma"],"falsifier":"A deep, high-resolution radio image of UGC 05771 near 1.7 GHz (for example with the VLA in its most extended configuration or with global VLBI plus short-spacing data) that either detects kpc-scale low-surface-brightness jet plasma, confirming the claim, or shows that the missing flux is not present as extended emission, which would refute it; a simpler check is whether the proposed extended plasma moves the source onto the peak-frequency–size relation.","tokens_in":28207,"feed_emoji":"🌠","tokens_out":7303,"duration_ms":61990,"temperature":0.7,"pith_summary":"Jet-driven feedback is widely invoked to explain how galaxies stop forming stars, yet direct evidence is hard to come by. This paper studies a nearby compact radio galaxy, UGC 05771, whose radio core is only 9 pc across according to VLBI imaging, and asks whether its jets nevertheless reach far into the host galaxy and disturb the interstellar medium. Using adaptive-optics near-infrared spectroscopy and optical integral-field data, the authors detect shocked molecular and ionized gas out to hundreds of parsecs and kiloparsec scales respectively, with line ratios and kinematics that point to shocks rather than star formation or supernovae. They argue that 70–80 per cent of the radio flux is missed by VLBI, implying kpc-scale jet plasma that is being resolved out, and that this plasma is shocking and churning the gas. The galaxy lies below the star-formation–gas-surface-density relation, tentatively suggesting that the jets suppress star formation, although the authors stop short of claiming definitive negative feedback.","feed_headline":"UGC 05771's jets stretch far beyond its 9-pc radio core","feed_subtitle":"Shocked gas out to kiloparsecs suggests a compact radio source can reshape its host galaxy.","key_machinery":"The argument turns on two pieces of evidence working together. First, the flux discrepancy: VLBI observations at 1.665 GHz recover only 20–30 per cent of the total single-dish flux, implying that 70–80 per cent of the emission is extended on scales larger than the VLBI field. Second, the shock diagnostics: the H2 1–0 S(1)/Brγ line ratio far exceeds the UV-excitation range, the [Fe ii] luminosity is an order of magnitude too high for supernovae, and the optical line ratios and velocity dispersions in the inner 2 kpc match shock excitation and rule out beam smearing. Together these identify the jets as being in the 'flood-and-channel' phase, in which the main jet stream creates bright compact radio structures while weaker streams inflate a low-surface-brightness bubble that shocks the surrounding ISM. This is the mechanism that lets a nominally pc-scale radio source affect gas on kpc scales.","core_discovery":"On the paper's own terms, the central discovery is that the young, compact radio source in UGC 05771 is not confined to the 9 pc structure visible in VLBI images. Comparing single-dish and interferometric radio fluxes shows that most of the 1.665 GHz emission is not recovered by VLBI, and the authors interpret this as low-surface-brightness jet plasma on kiloparsec scales, consistent with the near-infrared H2 1–0 S(1) and [Fe ii] emission seen within ~200 pc, and the shocked, high-velocity-dispersion ionized gas seen within ~2 kpc in optical data. They conclude that kpc-scale jet plasma is responsible for the line emission, accelerating gas outward at velocities too low to escape — a 'stalling wind' — and that the jet–ISM interaction may be inhibiting star formation, placing the galaxy about a factor of nine below the empirical star-formation–gas-surface-density relation, though this offset is not definitively attributed to the jets.","pith_inferences":["If the missing-flux interpretation is correct, deep, high-resolution radio imaging of other compact steep spectrum and gigahertz-peaked sources should reveal kpc-scale low-surface-brightness emission; UGC 05771 is a direct test.","The estimated source age of ~19 Myr from the bubble expansion model could be checked with spectral-aging or variability measurements; if the source is older, the 'flood-and-channel' picture would need revision.","The counter-rotating core hinted in the ionized-gas kinematics could be an independent signature of jet–disc interaction; if so, it would connect to simulations of jets propagating through clumpy discs."],"forward_implications":["The radio source in UGC 05771 is likely kpc-scale, not 9 pc, implying that compact radio sources can be substantially larger than their VLBI structure suggests.","Jets can couple strongly to the ISM even in low-power, young radio sources, creating a 'stalling wind' of gas that will not escape the galaxy.","The offset below the star-formation–gas surface density relation (about a factor of 9) is consistent with, though not proof of, jet-driven negative feedback.","Diffuse, low-surface-brightness jet plasma may be common in compact radio galaxies and can be missed by VLBI observations, affecting size estimates of such sources."],"supporting_citations":[{"why":"Supplies the VLBI images and flux measurements showing the source is 9 pc across and recovers only 20–30 per cent of the total flux.","marker":"de Vries et al. (2009)"},{"why":"Provides the radio spectrum, total flux densities, and the variability argument used to rule out beaming.","marker":"Snellen et al. (2004)"},{"why":"The companion study of 4C 31.04 that supplies the method connecting low-surface-brightness plasma to kpc-scale shocks and the free-free absorption density-pdf modelling used here.","marker":"Zovaro et al. (2019)"},{"why":"The simulation framework that defines the 'flood-and-channel' phase and the behaviour of jets in a clumpy ISM.","marker":"Sutherland & Bicknell (2007)"},{"why":"Simulations showing jets can create a 'galactic fountain' or stalling wind and inject turbulence into the ISM.","marker":"Mukherjee et al. (2016)"},{"why":"The empirical radio luminosity–jet power correlation used to estimate the jet power.","marker":"Ineson et al. (2017)"},{"why":"The turnover frequency–size anticorrelation used to argue UGC 05771 is likely much larger than its VLBI size.","marker":"O'Dea & Baum (1997)"},{"why":"The star-formation–gas-surface-density relation used as the baseline for the feedback comparison.","marker":"Kennicutt (1998)"}],"fun_headline_variants":["Jets in UGC 05771 reach kpc scales, not just 9 pc","Hidden kpc-scale jets shock gas in compact radio galaxy","Stalling wind: jets reshape host galaxy beyond radio core","UGC 05771's hidden jets shock gas and stifle star birth","Young radio galaxy's jets blow a stalling wind across kpc"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The inference that 70–80 per cent of the 1.665 GHz flux not recovered by VLBI is emitted by kpc-scale, low-surface-brightness jet plasma; if that missing flux is instead diffuse emission unrelated to the jets or is suppressed by absorption, the direct link between the jets and the kpc-scale shocked gas is substantially weakened.","fun_headline_variants_meta":{"raw":{"variants":["Jets in UGC 05771 reach kpc scales, not just 9 pc","Hidden kpc-scale jets shock gas in compact radio galaxy","Stalling wind: jets reshape host galaxy beyond radio core","UGC 05771's hidden jets shock gas and stifle star birth","Young radio galaxy's jets blow a stalling wind across kpc"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000236,"raw_usage":{"total_tokens":1555,"prompt_tokens":1051,"completion_tokens":504,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":667,"completion_tokens_details":{"reasoning_tokens":410}},"tokens_in":667,"tokens_out":504,"duration_ms":6201,"temperature":1.0,"reasoning_tokens":410,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-14T06:00:35.571588+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A deep, high-resolution radio image of UGC 05771 near 1.7 GHz (for example with the VLA in its most extended configuration or with global VLBI plus short-spacing data) that either detects kpc-scale low-surface-brightness jet plasma, confirming the claim, or shows that the missing flux is not present as extended emission, which would refute it; a simpler check is whether the proposed extended plasma moves the source onto the peak-frequency–size relation.","supporting_citations":[],"review_version":1}